Back-filling excavating blade assemblies are known, which are adapted to be fixed to a farm tractor and be operated by the conventional hydraulic system of said tractor However, such known assemblies require a special frame adapted to be detachably fixed to the underside of the tractor body. Such a frame must be removed when the tractor is used for other purposes Moreover, such frames must vary in size, shape and as to the location of the connecting brackets, depending on the various tractor models.
The three-point hitch system of a farm tractor cannot be used for operating an excavating blade, because no downward pressure can be exerted on the blade, since the hydraulic system of the three-point hitch system is normally capable of only raising the agricultural implement attached thereto. Also in conventional systems, the back-filling blade is curved and, therefore, is subjected to frictional forces from the earth when digging. It follows that the width of excavation is rather limited.